The most common method of producing watermarks in tax stamps. Fourdrinier (or dandy roll) is a paper-making process which presses a raised pattern into the newly formed wet surface of paper.


Capable of being broken. Refers to security labels which break up when removed or tampered with.

Fugitive ink

Solvent- or water-based inks that are printed onto a security document. When solvents or ink eradicators are applied to the document the fugitive ink spreads out creating a smudge, which denotes the attempt to tamper with the print.

Flexography (flexo) printing

A method of printing whereby a mirrored 3D relief of the required image is made in a rubber or polymer material. A measured amount of ink is deposited upon the surface of the printing plate, after which the print surface rotates, making contact with the print material...


A type of luminescence, describing the ability of some molecules or materials to absorb ultraviolet energy and immediately re-emit this energy within the visible spectrum, as a glowing light. The emitted light disappears as soon as the excitation light is...